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February 3-4 significant icing event for the interior, some sleet/snow possible. Coast mostly rain.


NJwx85
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31 minutes ago, NJwx85 said:

12z Euro gets extreme NNJ and the Hudson Valley below freezing by 12z. That's the key. It actually trended 1-2 degrees colder at this hour than the 00z run.

sfct.us_ne.png

prateptype_cat_ecmwf.us_ne.png

I get it that we should look at all the models up until game time but at this point shouldn't we put more stock in what the short range models  are showing ?

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1 hour ago, andyhb said:

Reminder to use the FRAM estimates available on PivotalWx for ice accretion and not ZR QPF. It's a much better (and scientifically sound) method for estimating/forecasting icing events.

Do you happen to know what the FRAM alogrithm does?  When I learned how simplisitic and scientifically questionable the Kuchera ratio algorithm was a few years back I was kind of taken aback, so was wondering whether the FRAM algorithm assumptions/calcs made sense.  They appear to be quite close for light ZR amounts, but pretty far apart for heavier amounts, with FRAM showing about half of the standard ZR  - wondering if the key is precip rate and FRAM assumes much more of the rain doesn't accrete in heavy rainfall.  Thanks.  

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8 minutes ago, HVSnowLover said:

NAM still showing over a quarter inch qpf of ice for Manhattan, Bronx, most of Brooklyn and Queens and northern Nassau.  I'd say impactful icing probably anywhere north of the 30 degree line which gets to about the Bronx/Westchester border. This is definitely a tough call. 

It drops quite a bit more liquid than the Euro between 18z and 00z. Temps really plummet after 12-15z.

qpf_006h.us_ne.png

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4 minutes ago, dmillz25 said:

The city and northern Nassau has been added to the WWA

URGENT - WINTER WEATHER MESSAGE
National Weather Service New York NY
355 PM EST Thu Feb 3 2022

NJZ006-107-108-NYZ072>075-078-176>179-041100-
/O.EXB.KOKX.WW.Y.0008.220204T1300Z-220205T0000Z/
Hudson-Western Union-Eastern Union-New York (Manhattan)-Bronx-
Richmond (Staten Island)-Kings (Brooklyn)-Northwest Suffolk-
Northern Queens-Northern Nassau-Southern Queens-Southern Nassau-
355 PM EST Thu Feb 3 2022

...WINTER WEATHER ADVISORY IN EFFECT FROM 8 AM TO 7 PM EST
FRIDAY...

* WHAT...Freezing rain expected. Total ice accumulations of up
  to one tenth of an inch.

* WHERE...Portions of northeast New Jersey and southeast New
  York.

* WHEN...From 8 AM to 7 PM EST Friday.

* IMPACTS...Difficult travel conditions are possible. The
  hazardous conditions could impact the morning or evening
  commute.
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OKX afternoon AFD:

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
The cold front pushes south through the forecast area Friday morning
with lowering temperatures falling slowly behind it. One of the
challenges for coastal areas regarding freezing rain is that a weak
wave of low pressure shifts through nearby which may delay the
timing of surface temps falling to freezing and below. For all
locations regarding PCPN type, a challenge will be whether, and how
quickly, the magnitude (temperature and depth) of the cold nose
beneath the warm nose aloft can introduce sleet as a PCPN type.
OKX afternoon AFD:

Forecast soundings show a relatively shallow cold nose that`s
marginally cold enough for the likelihood of liquid aloft refreezing
to sleet from the coast northward through around the I-84 corridor.
On the other hand, by the time surface temps are falling below
freezing for these areas, precip intensity should be lighter which
would increase the chances of refreezing (smaller droplets). Temps
aloft cool down to a level that would preclude rain or freezing rain
late in the day/early evening for most coastal sections, but mid
level drying should work against sleet or snow, so no snow or sleet
seems likely for the coast. Not much opportunity overall for snow
with this setup as temps in the warm nose don`t cool down enough in
time to coincide with deep moisture. Best chances of snow will be
well NW of the city late morning to early afternoon, but even this
is in question since mid levels will be drying with a lack of ice
nucleation - so maybe it remains a mix of freezing rain and sleet
there into the afternoon.

Surface temp forecast was based on a blend raw 2m NAM and GFS
temperatures. The colder GFS more closely mimics the HREF ensemble
mean with higher res data which picks up more on cold air drainage
down the Hudson Valley into the city. With that said, both GFS and
NAM have trended a little warmer in this regard from the previous
few run cycles.

Have decided to add the remainder of the NJ zones, NYC, and parts of
LI to the winter wx advisory where at least a few hundredths of
an inch of ice accretion is expected tomorrow.
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2 minutes ago, weathermedic said:
OKX afternoon AFD:

.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
The cold front pushes south through the forecast area Friday morning
with lowering temperatures falling slowly behind it. One of the
challenges for coastal areas regarding freezing rain is that a weak
wave of low pressure shifts through nearby which may delay the
timing of surface temps falling to freezing and below. For all
locations regarding PCPN type, a challenge will be whether, and how
quickly, the magnitude (temperature and depth) of the cold nose
beneath the warm nose aloft can introduce sleet as a PCPN type.
OKX afternoon AFD:

Forecast soundings show a relatively shallow cold nose that`s
marginally cold enough for the likelihood of liquid aloft refreezing
to sleet from the coast northward through around the I-84 corridor.
On the other hand, by the time surface temps are falling below
freezing for these areas, precip intensity should be lighter which
would increase the chances of refreezing (smaller droplets). Temps
aloft cool down to a level that would preclude rain or freezing rain
late in the day/early evening for most coastal sections, but mid
level drying should work against sleet or snow, so no snow or sleet
seems likely for the coast. Not much opportunity overall for snow
with this setup as temps in the warm nose don`t cool down enough in
time to coincide with deep moisture. Best chances of snow will be
well NW of the city late morning to early afternoon, but even this
is in question since mid levels will be drying with a lack of ice
nucleation - so maybe it remains a mix of freezing rain and sleet
there into the afternoon.

Surface temp forecast was based on a blend raw 2m NAM and GFS
temperatures. The colder GFS more closely mimics the HREF ensemble
mean with higher res data which picks up more on cold air drainage
down the Hudson Valley into the city. With that said, both GFS and
NAM have trended a little warmer in this regard from the previous
few run cycles.

Have decided to add the remainder of the NJ zones, NYC, and parts of
LI to the winter wx advisory where at least a few hundredths of
an inch of ice accretion is expected tomorrow.

Boy what a big ring around  the rosey discussion about there not sure what's going to happen exactly..

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